| Reinforced concrete(RC)moment-resisting frames(MRF)are one of the main lateral load resisting systems that are commonly used in buildings in seismic regions.In such frames,the rotational resistance of beam-column joints(B-CJs)is the main source of lateral stiffness of the frames.It will cause huge direct and indirect losses in the event of an earthquake.Sesimic damage of RC structures shows that traditional RC ductile structures are severely damaged after the earthquake,leaving large residual displacements and difficult to repair.The FRP-RC structure has high safety,high durability and high recoverability,which adapt to the new requirements of sustainable development society for infrastructure construction.In this paper,in order to improve the seismic performance of Reinforced concrete(RC)moment-resisting frames,especially the post-earthquake functionality and recoverability,glass fiber-reinforced polymers are used in RC moment-resisting frames,and the effects of related parameters on the seismic performance of GFRP-RC beam-column joint were analyzed;The seismic performance of new hybrid reinforcement concrete beam-column joints was explored.The cyclic response of beam-column joints were studied,the damage tolerance,carrying capacity,energy dissipation and restoring characteristics were compared.Meanwhile,a detailed seismic design method of GFRP-RC beam-column joint was proposed.The major research contents,methods and conclusions are as follows:(1)A unified model of FRP-RC rectangular cross-section was proposed,and simple closed-form code-compliant equation for determining bending capacity was proposed.The equation,was fully parameterized in terms of geometric properties and material constitutive relations,and then a detailed seismic design method of GFRP-RC beam-column joint was preliminarily proposed.(2)GFRP-RC beam-column joints were tested under lateral displacement reversals,the damage tolerance,carrying capacity,energy dissipation and reset characteristics were analysed by comparing GFRP-RC beam-column joints with traditional RC beam-column joints,tested parameterson included concrete strength,hoop ratio and axial compression ratio,the effects of these parameters on the seismic performance of the GFRP-RC beam-column joints were analyzed.The experimental results indicated that GFRP-RC beam-column joints are able to withstand significantly high lateral deformations without exhibiting brittle failure.The steel-RC beam-column jiont exhibited significantly higer energy dissipation and residual displacement than the counterpart GFRP-RC beam-column joint by 50% and 60%,respectively.(3)Hybrid reinforcement concrete beam-column joints were tested under lateraldisplacement reversals,the differences in hysteretic energy dissipation capacity and residual displacement were compared with RC beam-column joints and GFRP-RC beam-column joints.the feasibility of hybrid reinforcement concrete beam-column joints was verified,and the optimal hybrid reinforcement scheme was proposed. |
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